Need part numbers please/help please - MC9 headlights

[tnichol]

1979 MCI9 - on the road and need to replace the headlights (2 are out and the other 2 are very weak).  Everything seems to be stock in this bus, ground wires seems OK - I just think the bulbs are old/worn out.  Is there a replacement part number that I can use? I recall that these are 24V lights - remember reading threads about replacing with higher-end kits, and converting to 12V not looking to do that now.. I'm just looking for the part numbers to buy the bulbs and keep on rolling.  Any help would be greatly appreciated.   If this isn't something I can get in a regular truckstop or autoparts store - can y'all please tell me where I can order (supplier website or phone number?)

Sincerely,

Tim

[Busted Knuckle]

;(

[buswarrior]

Haven't seen many weak headlights, but I've seen lots of bad wiring.

Check the wiring/voltages/grounds before spending money on new bulbs.

happy coaching!
buswarrior

[mike802]

I have a 1983 Mc9 and my headlights are 12v stock.  sorry I can't help anymore that that.

[wildbob24]

Tim,

Every MC9 I've seen has had 12 volt headlights from the factory. As BK said, check your bulbs, they should be 12 volt. Usually, dim bulbs indicates bad grounds.

Bob

[Busted Knuckle]

;(

[bevans6]

I think there are three or even four ways your headlights could be connected.  I know that my MCI-5C, 1980 vintage, had 24 volt lights stock (first way) and was converted to 12 volt using MCI modules, one for each pair.  This is a retrofit kit from, I believe, TMC (second way).  There was a change to MC9's around 1982 I think that had them connected 12 volt bulbs in series (third way).  Sometimes owners simply wired them to the house 12 volt system or the bus Vanner fed 12 volt system (fourth way).

So if you have 24 volt bulbs, you can replace with 24 volt bulbs, after checking voltages etc, these are available on the Web, or possibly at larger truck supply houses.  You could decide to upgrade to Halogen with replaceable bulbs, H1 and H4 type bulbs are available in various wattages and 24 volts and with good optics in the housings make an excellent upgrade.  Same with 12 volt, I recently upgraded to H4 Hella's in my low beam positions.

Yet another complication is that the MC-9 came stock with dual 5.25" round bulbs, low/high and high on each side, and many have been converted to dual square bulbs. 

I have seen old style incandescent bulbs go dim rather than simply burn out, but it's rare.  Chase the voltages and grounds.  I would say do that first but frankly it may be easier to simply replace the bulbs with same and see what happens, and you should have a full set of spares on board anyway.

Brian

[tnichol]

>Yet another complication is that the MC-9 came stock with dual 5.25" round bulbs, low/high and high on each side, and many have been >converted to dual square bulbs.

yes what I've got is 4 round bulbs (2 on each side).  I'm asking how to purchase new ones to replace the ones I have.  If I can "upgrade" I'm happy to do it - but would prefer to just replace the bulbs for now - not the housing/not the wiring harness unless its required.   I took one bulb  out and found an autoparts store and the guy told me without a part number he can't help me.  How do I know what to buy?   Can someone tell me what part number so that I can replace the ones I have?   From what I'm seeing, and what I've been told I've got STOCK headlights for the MC-9.   I understand everyone wants me to check the wiring - ESP the ground.  I've done that to the best of my ability (I'm not an electrician - but I can follow a wire, and it seems to be still solidly ground). 

[Highway Yacht]

I'm asking how to purchase new ones to replace the ones I have.  If I can "upgrade" I'm happy to do it - but would prefer to just replace the bulbs for now - not the housing/not the wiring harness unless its required.   I took one bulb  out and found an autoparts store and the guy told me without a part number he can't help me.  How do I know what to buy?   Can someone tell me what part number so that I can replace the ones I have?   From what I'm seeing, and what I've been told I've got STOCK headlights for the MC-9.   I understand everyone wants me to check the wiring - ESP the ground.  I've done that to the best of my ability (I'm not an electrician - but I can follow a wire, and it seems to be still solidly ground).  

I don't think anyone here can tell you what part number you need to buy until you can determine exactly what you have as so many above have tried to explain. From what I am reading you could have either 12V or 24V headlights. The bus is 30 years old and any number of headlight/wiring modifications could have taken place in that 30 year time period and the headlights still appear stock. If it was me, I'd take a voltage tester and check the voltage at the headlights and determine if it was wired 24V or 12V. If you are getting a little over  12 volts, then I would take one out and carry it to an auto parts house and let them match it up. Most Auto Parts Chain stores such as Autozone usually will not help you if you don't have the part# since they soley operate from their computer screen, but most NAPA stores or Mom & Pop type Auto Parts places around here will be more than happy to match it up for you. If it was a little over 24 volts then you will probably have to take it to a major truck parts house to get it matched up. With the voltage tester, you will know exactly what voltage you are getting. If you are getting less than 12 Volts or less than 24 Volts then you have an electrical problem that will need to be resolved.

[Busted Knuckle]

;(

[tnichol]

" If it was me, I'd take a voltage tester and check the voltage at the headlights and determine if it was wired 24V or 12V."

Perfect. Understood. Someone could have rewired the system and screwed it up - its not sufficient to say that it "appears to be stock" because in 30 years alot could have been done.   Thank you all for the help. I'll check the voltage and then see if I can get someone to replace them depending on what the reading says. Roger that. OUT

[Ednj]

tnichol ,

On my 9 the low beam, on the 4 light system are = "Sylvania H5006" 

[bevans6]

Yep, for 12 volt lights the 5.75" round lights are H5001 for the high beams and H5006 for the combined high/low  beams.

http://www.amazon.com/Sylvania-H5006-Standard-35-Watt-Headlight/dp/B000CO7AIE/ref=pd_bxgy_auto_text_b
http://www.amazon.com/Sylvania-H5001-Standard-50-Watt-Headlight/dp/B000BLMJMA/ref=pd_bxgy_auto_text_b

Daniel Stern can supply high quality european type headlights that use replaceable H1 and H4 bulbs in either 12v or 24v.  http://www.danielsternlighting.com/products/products.html

Hope this helps

[Busted Knuckle]

Sorry I even tried to help!

[gumpy]

" If it was me, I'd take a voltage tester and check the voltage at the headlights and determine if it was wired 24V or 12V."

Perfect. Understood. Someone could have rewired the system and screwed it up - its not sufficient to say that it "appears to be stock" because in 30 years alot could have been done.   Thank you all for the help. I'll check the voltage and then see if I can get someone to replace them depending on what the reading says. Roger that. OUT

Well, in theory using the voltage tester might help, but it won't necessarily tell you what bulbs you have in there. If you measure 24 volts on the drivers side wires, you might assume you have
24 volt bulbs, but there a high likelyhood you'd be wrong.

MC9s came with 12v bulbs installed in series on a 24v feed. However, in the years preceeding the MC9, the bulbs were indeed 24v bulbs, and they transitioned to 12v bulbs in the very early MC9s. Yours is one of the very early MC9s if it is 1979, and therefore, it's entirely possible your bus came with 24v bulbs in it. The only way to know for certain is to trace the wiring and see how it's
wired, or look at the existing bulbs to see what they are (assuming someone didn't already make the mistake of putting 24v bulbs in place of the 12v bulbs; which would burn dimly  )